Technical Field
The present disclosure relates to a projecting device. More particularly, the present disclosure relates to a three-dimension light field construction apparatus.
Description of Related Art
When a two eyed viewer looks an object, each eye sees a slightly different view due to binocular parallax and motion parallax, and a three-dimension (3D) image is observed by view's brain fusing the different views together. Because the eyes of humans are located at different lateral positions on the head, and the axial distance between two eyes is about 6 to 6.5 centimeters, the differences are mainly in the relative horizontal position of objects in the two images. These positional differences are referred to as horizontal disparities or, more generally, binocular disparities. Motion parallax means the differences in the image of an object over time with observer movement.
The development of 3D light field construction is based on the principle of stereopsis, which using spectroscopic techniques to make eyes receive different images to form the stereoscopic 3D image. There are two categories of 3D light field construction, 3D with glasses (or headset) and autostereoscopy 3D display. The 3D with glasses or headset is a first system of displaying stereoscopic, and has a range of applications but is inconvenient to limit by the need to wear glasses or headset
A conventional autostereoscopy 3D display uses multiple projectors to generate different light fields with different viewing angles, it has the advantage of glassless, but is bulk, difficult to set and calibrate.
Reference is made to FIG. 1, which is a schematic view of a conventional three-dimension light field construction apparatus. The three-dimension light field construction apparatus includes a projector 10, a rear-displaying unit 12, and a parallax barrier 14. The rear-displaying unit 12 is arranged between the projector 10 and the parallax barrier 14. The projector 10 projects an imaging beam, the imaging beams projected by the projector 10 are projected to a plurality of particular areas behind the parallax barrier 14 while switchable apertures of the parallax barrier 14 allow the imaging beams passing therethrough. In particular, the particular areas are viewing areas 160, 162, and 164 on a viewing plane 16.
The rear-display unit 12 includes an axial-symmetry Fresnel lens 120 and a diffuser 122. The Fresnel lens 120 is close to the projectors 10 and makes the imaging beams having divergence to be collimated beams. The diffuser 122 diffuses the collimated beams in all directions.
The parallax barrier 14 is, for example, liquid crystal barrier. The parallax barrier 14 receives light passing the rear-displaying unit 12, and constructs light fields by switching at least one switchable aperture to be opened and allows corresponding imaging beam passing therethrough. For example, when switchable aperture S01 is opened, a light field is constructed on the viewing area 164, and a full light field can be constructed by switching the parallax barrier 14 from switchable aperture S01 to S61 in serial.
In order to observe a 3D image, the width of the switchable aperture must be appropriately designed to ensure the left eye of a viewer only sees the left view and the right eye of the views only sees the right view. This ensure that each eye of the viewer sees the appropriate image allowing the viewer's brain create a 3D image.
However, the parallax barrier 14 only allows imaging beams passing through the opened switchable aperture, the fact which results in an inefficiency of light utilization and small-scale system, and shields off most of imaging beams projected by the projectors 10.